” Certainly the Archean mantle 2.5 to 3.8 Ga was hotter than is the modern mantle.
” Certainly the Archean mantle 2.5 to 3.8 Ga was hotter than is the modern mantle.Tags: Play School Business PlanBusiness Plan Pricing Strategy ExampleEffects Of Advertising EssayWhat Is An Abstract When Writing A PaperHow To Write A Correct EssayMath Homework For 1st GradeDissertation Online
Plate Tectonics Ever since the beginning on time, Humans believed the ground is solid and immobile. The Earth is every-changing and continually in motion.
The stability of the Earth is not at all what we think it is.
The most important consideration is that hotter asthenospheric mantle is slightly (~1%) less dense than colder overlying lithospheric mantle, so these want to change places.
This sometimes happens during detachment and delamination of lithospheric mantle but generally happens by subduction, the end-on sinking of lithosphere beneath asthenosphere.
Yes it was mantle convection, but was convection driven by hot deep mantle rising or cold dense lithosphere sinking?
Geodynamicists soon began investigating and now they tell us that it is mostly the sinking of dense lithosphere in subduction zones, pulling the plates and moving them.
The crust has two types, the oceanic and continental; they both differ because of composition.
Stern Two of my favorite topics of geoconversation are how new subduction zones get started and when in Earth’s history did plate tectonics begin?
This follows from a strict interpretation of the Principle of Uniformity, which basically states that “the present is the key to the past”.
Following strict Uniformitarianist logic, because we definitely have plate tectonics today, Earth must have always had plate tectonics.